Technical Field
The present specification relates to a hybrid vehicle, and particularly relates to a hybrid vehicle provided with an internal combustion engine and an one-way clutch configured to prevent the reverse rotation of the internal combustion engine.
Description of the Background Art
There is known such a hybrid vehicle that is configured to include an internal combustion engine (engine), a first and a second rotating electric machines (motor generators), and an one-way clutch configured to prevent the reverse rotation of the internal combustion engine and provided between a rotation shaft of the internal combustion engine and a power split device.
Japanese Patent Laying-Open No. 2002-12046 discloses an example of such vehicle. In the vehicle, in order to prevent the engine from being driven to rotate in the reverse direction along with the motor generator, an one-way clutch is provided between a casing and an output shaft, to which the rotation of the engine is transmitted.
According to the vehicle disclosed in Japanese Patent Laying-Open No. 2002-12046, when a motor torque is generated by the motor generator in the direction of lowering the engine rotation speed, in the case where the engine rotation speed takes a negative value, it is determined that a malfunction has occurred on the one-way clutch.
However, even though the occurred malfunction is not firstly present on the one-way clutch, if the vehicle is made to move under a malfunctioning state, an unnecessary force may be applied to the one-way clutch, resulting a damage to the one-way clutch.
In such case, it is desirable to notify the driver about the malfunction before the damage to the one-way clutch occurs. On the other hand, if the vehicle totally goes out of operation to prevent damage to the one-way clutch, it is not possible to perform escape running. It is desirable to allow the driver to make escape running.
Moreover, even when the vehicle is not moving on its own power but is being towed, the one-way clutch may be damaged depending on the towing direction, and thereby it is necessary to prevent the one-way clutch from being damaged.